Do not borrow money where you buy the car is a rule that I was taught in Australia, however due to promotional offers of 3.9% I let my guard down and paid the penalty for it.
I had to pay a w650,000 application fee to get my low rate loan and I lost w500,000 of discount bringing the real rate I am paying to over 12%, and most of that was paid upfront.
Go to your bank and get an unsecured loan.
If you can't do that because your bank won't cooperate, change banks, but give up on the bank loan because a lot of credit enquiries will reduce your chances of getting the loan.
So if you still need a car, and you don't have the cash then you will have to get dealer finance here are my pointers.
1. You will need your spouse to guarantee your loan. Korean institutions haven't heard of The UN's Committee on the Elimination of Racial Discrimination's ruling of Habassi v. Denmark so unless you want to take up the fight, your spouse will have to sign.
2. If you can, choose a smaller town to buy your car, this means that the car dealer and the finance company people will know each other well. It may take time but if you form a relationship with the dealer, the dealer will take care of every stage where the finance company comes back with a reason not to make the loan.
3. Be patient, it will take time.
It may have been easier to put it in my wife's name, but as my wife is a homemaker, that wasn't an option either.